Photo: Nlpictures · Public domainNew Lenox’s winters are colder but less snowy than most of the U.S.
A typical July afternoon reaches 84°, a January night drops to 17°, and about 17 inches of snow falls in a normal winter.
A year in New Lenox at a glance
Each month’s typical high and low, and what it brings.
What stands out about New Lenox’s climate
Compared with towns across the U.S., with New Lenox’s place in Illinois beside it.
What a year in New Lenox feels like
Typical highs and lows by season and by month, from NOAA’s 30-year normals.
About 188 frost-free days a year
In half of years the last 32° night comes by April 19 and the first by October 25. Frost and day counts come from NOAA’s station at Joliet Brandon Rd Dam, IL, 7 miles from the town’s center, 140 ft lower.
The 2023 USDA map puts New Lenox’s center in zone 6a: the coldest night of a typical winter, averaged over 1991–2020, reaches about −9°. Plant labels use the zone; frost dates tell you when to plant.
Freezing nights by month
Average nights at or below 32°
90° days by month
Average days at 90° or more
About 17 inches of snow a winter
Snow, measured at Joliet Brandon Rd Dam, IL, falls mostly in February. Precipitation (rain plus melted snow) adds up to 39 inches a year; May is the wettest month and February the driest. Rain or snow falls on about 123 days a year.
Rain + melted snow by month
Inches of water
Snowfall by month
Inches of snow
Heating and cooling a home in New Lenox
88% of the work is heating, so the furnace matters far more than the air conditioner. Months averaging under 55° run from October through April.
Degree days add up how far each day’s average falls below (heating) or rises above (cooling) 65° over a year. NOAA normals at Joliet Brandon Rd Dam, IL.
Living with New Lenox’s climate
What the numbers mean for a garden, a free afternoon and a bad-weather day.
188 frost-free days in zone 6a. The last frost comes by Apr 19 in half of years, so many gardeners wait a week or two past that to set out tomatoes. The first fall frost comes by Oct 25.
Months with highs of 62–84° and lows of 40° or more: May, June, August, September and October. 2.3 miles of trails are waiting.
Parks & trails →Of the yearly building losses FEMA expects in New Lenox from natural hazards, river flooding is the largest share (57%); heat waves, cold waves, winter storms and ice storms together are 22%. Normals are averages; the hazards page covers the extremes.
Natural hazards →New Lenox and its neighbors
Every town next door is within a degree of New Lenox in January and July, closer than the 5 km grid can tell apart. Tap a town to see its climate.
Climates most like New Lenox’s, farther away
TownRatings’ own comparison of NOAA 1991–2020 normals, not a NOAA product: places of 5,000+ at least 150 miles away, one per state, closest on January low, July high, precipitation and snow.
| Town | Jan. low | July high | Precip. | Snow |
|---|---|---|---|---|
| New Lenox, IL | 17° | 84° | 39" | 17" |
| Van Wert, OH | 19° | 84° | 39" | 17" |
| Fairfield, IA | 14° | 85° | 38" | 22" |
| Bluffton, IN | 19° | 84° | 41" | 23" |
| New Brighton, PA | 21° | 84° | 41" | 20" |
Temperatures and rain come from NOAA’s 5 km grid, so each town gets its own value. Snow and frost-free days come from the nearest weather station, so neighbors often share them.
Warmer than it used to be
The last 30 years in New Lenox averaged 1.2° warmer than the 1900s. The biggest change is in December (+2.4°).
A smaller shift than in 60% of U.S. towns.
Change by month
The two periods overlap (1991–2000 is in both), which makes the gap a little smaller than it would be between separate periods.
How New Lenox compares
Against 12,954 U.S. towns of 2,500 or more (one per 5 km climate cell), with New Lenox’s place among Illinois’.
New Lenox weather by month
Highs, lows and precipitation from NOAA’s grid at New Lenox’s center; snow, wet days and snow on the ground from Joliet Brandon Rd Dam, IL. 1991–2020 normals.
| Month | High | Low | Rain + melt | Snow | Wet days | Snow on ground | 30-yr range |
|---|---|---|---|---|---|---|---|
| January | 32° | 17° | 2.1" | 5.0" | 11 | 12 | 15° – 36° |
| February | 36° | 20° | 1.9" | 6.2" | 9 | 8 | 15° – 39° |
| March | 48° | 29° | 2.4" | 2.1" | 10 | 2 | 30° – 54° |
| April | 61° | 39° | 3.9" | 0.1" | 12 | 0 | 41° – 56° |
| May | 72° | 50° | 4.6" | 0.0" | 12 | 0 | 55° – 67° |
| June | 81° | 59° | 4.5" | 0.0" | 11 | 0 | 66° – 75° |
| July | 84° | 64° | 4.2" | 0.0" | 9 | 0 | 69° – 80° |
| August | 83° | 62° | 4.1" | 0.0" | 9 | 0 | 67° – 78° |
| September | 76° | 55° | 3.4" | 0.0" | 8 | 0 | 60° – 70° |
| October | 64° | 43° | 3.4" | 0.0" | 10 | 0 | 49° – 59° |
| November | 49° | 32° | 2.6" | 0.3" | 10 | 0 | 33° – 49° |
| December | 37° | 22° | 2.2" | 3.2" | 11 | 6 | 16° – 39° |
| Year | 60° | 41° | 39.4" | 16.9" | 123 | 28 |
How much a month can swing
A normal is an average. February swings the most: from 1991 to 2020 its average ranged from 15° to 39°. June is the most reliable, staying within 8°.
Where New Lenox’s numbers come from
Normals are 30-year averages, not a forecast. How TownRatings reads climate data →
- Temperatures and precipitation: NOAA’s gridded 1991–2020 normals for the 5 km cell at New Lenox’s center.
- Snow: Joliet Brandon Rd Dam, IL.
- Frost, freezing nights, 90° and 100° days, heating and cooling: Joliet Brandon Rd Dam, IL, 7 miles from the town’s center, 140 ft lower; the nearest station that passes our checks for distance, height and agreement with the grid.
- Growing zone: USDA Plant Hardiness Zone Map, 2023. USDA Agricultural Research Service and PRISM Group, Oregon State University, prism.oregonstate.edu/phzm, accessed 8 Oct 2026.
- Then and now: NOAA’s gridded normals for 1901–2000 at the same cell.
- Storms and extremes: FEMA National Risk Index (expected annual losses to buildings).
Common questions about New Lenox’s climate
What is the weather like in New Lenox?
A typical July afternoon reaches 84°, a January night drops to 17°, and about 17 inches of snow falls in a normal winter. Colder January nights than 78% of U.S. towns; cooler July afternoons than 58% of U.S. towns.
How cold does it get in New Lenox in winter?
January nights average 17°. About 126 nights a year reach 32° or below and 8 reach 0° or below. In the coldest January of the last 30 years the month averaged 15°.
How much snow does New Lenox get?
About 17 inches in a normal winter at Joliet Brandon Rd Dam, IL, most of it in February, with snow on the ground about 28 days a year.
How hot does it get in New Lenox?
July, with a typical high of 84° and a low of 64°. About 15 days a year reach 90° (Joliet Brandon Rd Dam, IL).
When is the first and last frost in New Lenox?
In half of years the last spring frost (32°) comes by April 19 and the first fall frost by October 25, about 188 frost-free days, at Joliet Brandon Rd Dam, IL.
What growing zone is New Lenox in?
Zone 6a on the 2023 USDA Plant Hardiness Zone Map: the coldest night of a typical winter reaches about −9°.
What is the best time of year to visit New Lenox?
By one simple rule (highs of 62–84° and lows of 40° or more), May, June, August, September and October. The rule is ours, not NOAA’s; the month table has the numbers to judge by.
Is New Lenox getting warmer?
Yes: 1991–2020 averaged 1.2° warmer than 1901–2000 on NOAA’s grid. A smaller shift than 60% of U.S. towns.
Neighbors talk weather
Gardens, snow, and the best days of the year in New Lenox.
Source: NOAA NCEI U.S. Climate Normals, 1991–2020 and 1901–2000; USDA/PRISM 2023 hardiness zones; FEMA National Risk Index. Today’s forecast: National Weather Service.